Exploring Density

How could I make an egg float on water?(how do submarines work?)
Griffin McLaughlin
Grade 6


  • The egg will sink to the bottom because there is no air to hold it up inside the shell, and it is very heavy.
  • The egg will still sink to the bottom even though salt is added to the water.


This project has very little research involved.


The parts that change are:

1. Oil

2. The salt

The parts that dont change are:

amount of water

the egg


What I did in part one of the experiment:

1. Added 2 cups of water to the glass

2. Dropped egg in

3. The egg did not float

4. Scooped egg out

5. Added in 1/6 cup of salt

6. Stirred to disolve salt

7. Dropped egg in

8. Within 30 seconds the egg was floating at the top

Part 2 of the experiment:

1. Added in 2 cups of water

2. Added in ~3 tbsp of olive oil

3. oil floated on water

4. dropped egg in

5. egg sank to the bottom (didnt float)

6. scooped egg out

7. Inserted 1/6 cup of salt

8. Stirred to dissolve

9. Oil created "tornado" around the spoon

10. Dropped egg in

11. Egg floated to the top of the water but below the oil



During part 1 (without oil)

Egg bounced twice on the bottom and then stopped.

  • Egg floated to halfway point and then floated to 1 cm from the top of the glass.
  • 10 seconds later 5mm from top.
  • touched the top in 30 seconds.
  • egg bobbed at top.


During part 2 (with oil)

  • Little bubbles formed on the surface when oil added.
  • The oil floated on the water.
  • The Egg floated between the water and the oil.


What is the outcome of the experiment.

Even though the egg was heavy, the water held it up when the salt was added because the salt changed the density of the water. The egg could then float on water because the salt made the water more dense so that the molecules inside became tighter and held the egg up. The oil is less dense than the water so it floated on top. The egg was more dense than the oil so it floats in between the oil and the water.

The least dense substance in this experiment was the oil the most dense was the salt water.



What I have learned from this experiment.

  • Temperature matters. Because the first few times I did this experiment they didn't work because the egg needs to be room temperature and the water needed to be warm.
  • The amount of things matters. Too little water or salt and the egg won't float.
  • Some things are more dense than others. Like when the oil was floating on the water it is because the oil is less dense so it floats on the water.
  • The salt increases the density of the water causing it to be more dense than the egg so it can hold it up.
  • The oil stays the same density and pushes the egg down so it is just below the oil in part 2 of the experiment.


This is applicable to real life because of the fact that some things have different densities. It can be used to solve problems, for example cleaning up oil spills. Density also affects large scale engineering projects. When a submarine is trying to go underwater it fills up its tanks with water to make the density higher and when it wants to surface it empties the tanks to make the density less.


Sources Of Error

What went wrong?

The first few times I did it it didnt work because I didnt get the tempratures right.

The other problem was I wasnt adding enough salt.

That was it for the problems


Here is the list of websites I used



The book I used was:

88 1/2 science experiments by Nick Arnold


I did the experiment on my own and my dad helped set it up again so we could take the pictures. My mom helped with the pictures and the overall presentation. The video was taked by Mrs.Cooksley (Deirdre Cooksley).

The video shown in the presentation is on youtube and was posted by AACT Connect. https://www.youtube.com/watch?v=WGFJqTmjz84